Nerve, optic
The optic nerve connects the eye to the brain. The optic nerve carries the impulses formed by the retina. The retina is the nerve layer that lines the back of the eye that senses light and creates impulses. These impulses are dispatched through the optic nerve to the brain, which interprets them as images. Using an ophthalmoscope, the head of the optic nerve can be easily seen. It can be viewed as the only visible part of the brain (or extension of it). The optic nerve is the second cranial nerve. The cranial nerve emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. There are twelve cranial nerves. In terms of its embryonic development, the optic nerve is a part of the central nervous system (CNS) rather than a peripheral nerve. The word "optic" comes from the Greek "optikos", pertaining to sight. Aside from the optic nerve, the eye has a number of other components. These include the cornea, iris, pupil, lens, retina, macula, and vitreous. The cornea is the clear front window of the eye that transmits and focuses light into the eye. The iris is the colored part of the eye that helps regulate the amount of light that enters the eye. The pupil is the dark aperture in the iris that determines how much light is let into the eye. The lens is the transparent structure inside the eye that focuses light rays onto the retina. The retina is, as mentioned, the nerve layer that lines the back of the eye, senses light and creates impulses that go through the optic nerve to the brain. The macula is a small area in the retina that contains special light-sensitive cells and allows us to see fine details clearly. The vitreous humor is a clear, jelly-like substance that fills the middle of the eye. In sum, the optic nerve is uniquely a part of both the eye and the brain. It is embryologically the brain's envoy to the eye and functionally the eye's envoy to the brain.

Medical dictionary. 2011.

Look at other dictionaries:

  • Optic nerve — This article is about the anatomical structure. For the comic book series, see Optic Nerve (comic). For the album about David Wojnarowicz, see Optic Nerve (CD ROM). Nerve: Optic Nerve The left optic nerve and the optic tracts …   Wikipedia

  • Optic chiasm — Brain: Optic chiasm Visual pathway with optic chiasm (X shape outlined, red) (1543 image from Andreas Vesalius Fabrica) Latin chiasma opticum Gray s …   Wikipedia

  • Optic tract — Brain: Optic tract The left optic nerve and the optic tracts. Latin tractus opticus Gray s subject #189 814 …   Wikipedia

  • optic nerve — Anat. either one of the second pair of cranial nerves, consisting of sensory fibers that conduct impulses from the retina to the brain. See illus. under eye. [1605 15] * * * ▪ anatomy   second cranial nerve, which carries sensory nerve impulses… …   Universalium

  • Optic atrophy — Infobox Disease Name = PAGENAME Caption = The left optic nerve and the optic tracts. DiseasesDB = 9241 ICD10 = ICD10|H|47|2|h|46 ICD9 = ICD9|377.1 ICDO = OMIM = MedlinePlus = eMedicineSubj = eMedicineTopic = MeshID = D009896 Optic atrophy is the… …   Wikipedia

  • Optic radiation — Brain: Optic radiation Colour coded diagram showing radiations in quadrants from retinal disc through the brain Latin radiatio optica NeuroNames …   Wikipedia

  • optic nerve — noun the cranial nerve that serves the retina • Syn: ↑nervus opticus, ↑second cranial nerve, ↑optic tract • Hypernyms: ↑cranial nerve • Part Holonyms: ↑visual system, ↑ …   Useful english dictionary

  • Optic neuropathy — Classification and external resources ICD 10 H46 The optic nerve contains axons of nerve cells that emerge from the retina, leave the eye at the optic disc, and go to the visual cortex where input from the eye is processed into vision. There are… …   Wikipedia

  • Optic disc drusen — Classification and external resources ICD 10 H47.3 ICD 9 377.21 …   Wikipedia

  • Optic nerve hypoplasia — Classification and external resources ICD 10 Q07.81 ICD 9 377.43, 743.57 …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”